Memory

If you believe our memory is like indelible ink, I'm with you. We thought we experience and remember anything - the way we celebrated our child's first birthday, the first "papa" she said, the first day of school. Who won't?

And then I brought with me a book by the neuroscientist Lisa Genova, Remember, during our family vacation this weekend. I come to appreciate how episodic memory about an autobiogrphical event can be warped. In the words of Lisa Genova, retrieval and reconsolidating an episodic memory is like hitting SAVE in Microsoft Word. Every time we recall an episodic memory, we overwrite the earlier version of the memory and update it. Any edits we've made are then saved to to the new version in our neural circuits. The old one is gone.

We happened to bring our daughter to the Kowloon Park this time. And then I noticed that she cannot recall having visited the large public park housing flamingos. Let me be honest: I have to look through my photo album to find out that it has been more than eight years since her last visit of Kowloon Park.

Now that I understand how fallible our episodic memory can be, I must mention a more stable and long-lasting memory: muscle memory. The memory for how to do things, as it turns out, is quite different from the memory for what happened. Muscle memory is unconscious, and remembered below our awareness. Once learned, the motor skills can be retrieved effortlessly. That's why my daughter doesn't have to think about how she's going to swing her body across the monkey bar at the Kowloon Park playground. Easy-peasy.